Andor Technology iXon Ultra 897 User Manual page 154

TUTORIAL 2
Andor software – from the Command menu on the Main Window, select
the option Command Line. Type in the command - ?gettemperature() –
and click on Execute. Furthermore, with electron multiplying technology,
operation at a lower temperature reduces darkcurrent, which would
otherwise be amplified in the gain register and appear as spurious noise
spikes (the extent of which depends on exposure time). The extensive
cooling performance of the iXon can essentially render this noise source
negligible.
Rather than carrying out this procedure with the sample to be scanned
within the actual experiment, an alternative is to perform a serial dilution
within microtitre wells of chemiluminescent material (e.g. Horse Radish
Peroxidase/luminol/peroxide) spanning a concentration range close to that
expected from the experiment. The maximum exposure time determined
from the strongest signal (E1) can be used with the exposure time (E2)
needed to exceed the cut-off S:B threshold in order to work out the
minimum number of accumulations required at E1 exposure and the gain
level applied. A neighbouring blank well (without chemiluminescent
material) can be used to represent background levels. Furthermore, this
simple test platform could also be used to determine actual gain levels, as
an alternative to the stable light source recommended in tutorial 1.
Section 7. 3
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